Telephone-exchange system.



S. B. WILLIAMS, JR. mzmoweexcumee SYSTEM. APPLICATION FILED DEC.8, 1916.

1 Q27 9,8 1 1 Patented Sept. 24, 1918.

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S. B. WILLIAMS, JR.

TEIQEPHONE EXCHANGE SYSTEM.

APPUCATION HLED 050.8. 916. 1 ,279,81 1 Patented Sept. 24, 1918.

2 SHEETSSHEET 2,.

//4 WM for: Samue/B. M/flams J? UNITED STATES PATEN T OFFICE.

SAMUEL B. WILLIAMS, an, or BROOKLYN, NEW. YORK, ASSIGNOR 'ro WESTERN ELEC- TRIO COMPANY, INCORPORATED, or NEW YORK, N. Y., A CORPORATION OF NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

Specification of Letters Patent.

Patented Sept. 24, 1918.

To all whom it may concern:

Be it known that I, SAMUEL B. WILLIAMS, J12, a citizen of the United States, residing at Brooklyn, in the county of Kings and State of New York, have invented, certain new and useful Improvements in Telephone- .xchange Systems, of which the. following is a full, clear, concise, and exact description.

This in ention relates to telephone exchange systems wherein a calling line is automatically associated with a connecting circuit by a non-num\ rical switch upon the removal 'of the receiver at the substation of such line, and particularly to such a system wherein, during light load hours, as, for example, during the night, all incoming calls are automatically concentrated upon a particular operators position, the other positions being made artificially busy. It fre quently happens that all the connecting circuits terminating at such positions, apportioned to a particular group of lines, are busy when another call is initiated in such group. This call therefore has to wait until one of the connecting circuits becomes idle.

It is the object of thisinvention to provide an improved arrangement for systems of this type, wherein, in the event of all the connecting circuits of a particular line group becoming busy, the initiation of a call in such group will automatically remove the artificial busy condition of the other positions, whereupon one of the connecting cir cuits thereof will automatically take the call,-

which the night operator can then attend to.

In accordance with this invention, the initiation of a call sets in operation an electro-responsive timing device, and if the line initiating such call is not extended to a connecting'circuit within a predetermined interval, such device renders the busy connecting circuits at the other positions accessible to the calling line, whereupon the line is auto matically extended to one of such connecting circuits.

More specifically, a train of slow relays is employed which operate successively 'upon the energization of any line relay, and each relay is maintained energized in a circuit dependent upon the preceding rel'ay. The last one of these slow relays operates a relay which locks itself in a circuit closed as long as the line relay is energized, "and connects interval, retracts a relay, which, when operated, renders the connecting circuits non-busy, to the back contact of the last slow relay and opens the whereupon the calling line is automatical'ly extended to one of such connecting circuits.

If, as is usually the case, the calling line is extended and the line relay rendered inert before the last slow relay retracts its armature, the locking circuit referred to is opened at the time the last slow relay deenergizes, and consequently the circuit of the relay which removes the busy condition of the connecting circuits is not-closed.

The invention will be more readily understood when described with reference to the accompanying drawings, wherein Figure 1 indicates a calling line and the answering end of a connecting circuit, and Fig. 2 a called line and the calling end of the connecting circuit.

Uponthe removal of the receiver at-substation A, the line relay LR is energized over the calling line circuit. This relay, in attracting its left armature, grounds the multiple 101 of the calling line, and, in attracting its right armature, energizes relays 102, 103, common to the group of lines contain-1 ing substation A. Relay 102, in attracting its right armature, grounds commutator multiple segment 104 substation A belongs to render the group calling. Relay 103, in attracting its right armature, closes the following. circuit to energize the escape magnet 106 of the linefinder side switch; free pole of battery, primary stopping magnet PM, escape magnet 106, side-switch arm 1, armature and back contact of magnet PM, armature and back contact of magnet SM, conductor 108, right armature and front contact'of relay 103, conductor |109, conductor 200, outer armature and back contact of relay 201, conductor 202, armature and back contact of the canin of the group to which normally-closed contact 292 of key is to and front contact of relay 102.

ground. Magnet PM does not energize in this circuit. The escape magnet 106 is constructed to release the side switch from position to position upon its energization.

In position 2, arm 1 connects magnet PM over the back contacts of magnets PM, SM, to grounded conductor 108, whereupon the finder brush shaft 119 is given a primary movement .by the operation'of such magnet PM. In position 2, arm 2 closes the following circuit for relay TR: free poleof battery, magnet SM, arm 2, left winding of relay TR, armature and back contact of magnet SM to grounded conductor 108. This relay is adapted to attract its armature upon the closure of this circuit, but magnet SM remains inert. Relay TR, at its inner armature and front contact, connects the escape magnet over arm 3 and its second contact to the commutator brush 115. When brush 115 encounters the calling commutator segment 104, now grounded, escape magnet 106 energizes over the following circuit, and releases the side switch into position 3: free pole of battery, magnets PM, 106, conductors 117, 118, armature and front contact -of relay TR, arm 3 and its second contact,

conductors 120, 130, commutator brush 115, segment 104, now grounded at the armature Arm 1, in moving out of position 2, opens the circuit of magnet PM, thus stopping the primary movement of the finder brush shaft 119 with a set of brushes 1 10, 111, 112 in operative relation to multiples of the calling line group containing those of the calling line 101, 113 and 114. I i

In position 3, relay TB is energized over' the following circuit: free pole of battery, magnets PM, 106, arm 2 and its third contact, left winding of relay'TR, armature and back contact of magnet SM, groundedconductor 108. Magnets PM and 106 do not energize in this circuit. Belay TR, at its outer armature and front contact, closes the following circuit to operate the secondary stepping magnet SM to drive the brushes 110, 111 and 112 over the multiples containing those of the calling line 101. 113 and 114: free pole of battery, magnet SM, outer armature and front contact of relay TR, arm 1 and its third contact, armature and back contact of magnet PM. armature and back contact of magnet SM, to grounded con- When, however, the brush 112 reaches the calling line-multiple 114-, relay TR becomes deenergized, and, since ground is present on multiple 101 of the calling line, the following circuit. is closed for escape magnet 106: free pole of battery, magnets PM, 106, conductors 117, 118, inner armature and back contact of relay TR, arm 5 and its third contact, brush 110, terminal 101, to ground at the left armature and front contact of relay LR. Magnet 106 upon its energization, releasesthe side switch into position 4. Thus, the finder brushes 110, 111, 11.2 remain on the calling line multiples 101, 113, 114. In position 4, the calling line is extended by arms 4-and 5 to the conductors 121, 122, whereupon the calling supervisory relay 203 is energized over the callin line circuit.

In position 4, arm 3 0 the finder side switch closes the following circuitto energize the cut-off relay C0 of the calling line: free pole of battery, resistance 206, conductors 214, 125, arm 3 and its fourth contact, conductor 120, brush 112, terminal 114, cutofl relay (0 to ground. This potential applied to multiples 114 by brush 112, holds relay TR of a moving finder energized over its right winding as the brush 112 of such finder wipes over such multiples, as hereinbefore described. Relay CO. in attracting its armatures, deenergizes the line relay LR, which, in retracting its left armature. removes the calling condition from the multiples 101,of the calling line, and, in retracting its right armature, denergizes group relays 102, 103. Relay 102, in retracting its right armature, removes the calling condition from the con'nnutator multiples 104 of this group.

Relay 203, in attracting its armature, op-

erates a relay 204, which lights the calling lamp 240, whereuponthe operator depresses listening key -K, which connects her headin this circuit. Relay 205, byattractingits armature, closes one break in the circuit of winding 210 of the operators head-set.

The operator now asks the calling party the number of the line wanted. The talking circuit between the operator and the calling party will not be traced in detail since it is readily apparent, from the drawing. The operator now tests the line in the well-known manner, by touching the tip of calling plug 211 to the sleeve of the jack 212. Ifthe line is busy, relay 209 energizes and in attracting its armature produces a click in the operatoi 's telephone in the well knov. r

manner. In the' absence of a click in her telephone, the operator inserts the plug into the jack, whereupon sleeve rela 213 is energized in series with the cut-off relay of the called line. Relay 213, in attracting its armature 251, connects conductor231 to the tip of the plug, and in attracting its armature 252, energizes relay 201 and lights lamp 233. In attracting its armature 253, relay 213 deenergizes relay 204, extinguishing the lamp 240. Relay 201, in attracting its armature, closes the following circuit for a relay 226 adapted to apply ringing current to the called line: free pole of battery, inner armature and front contact of relay 201,'c0nductor 227. relay 226, armature and back contact of relay 228, and armature and back contact of relay 229 to ground. Relay 226, in attracting its armatures, connects current from the generator 274 to the called line. \Vhen the called party removes his receiver, relay 229 attracts its armature, thus removing the shunt around relay 228, which thereupon energizes. Relay 228, in attracting its armature, locks itself to ground andshunts out relay 226. which, in retracting its armatnrcs, opens the ringing circuit and reconnects the talking conductors to the tip and ring of-the calling plug 211. The called supervisory relay 241 is thereupon energized over the called line, and, in attracting its armature, extinguishes supervisory lamp 233. The parties may now converse.

Upon the termination of the conversation and the replacement of the receiver by the calling party relay 203 becomes deenergized and closes the following circuit for relay 204: ground, contact 292 of key K, conductors 291, 290, armature and back contact of relay 203, conductor 202, outer armature and front contact of relay 201, conductors 290', 291, relay 204, free pole of battery. Relay 204, in operating, lights the supervisory lamp 240.

\Vhen the called party hangs up his receiver, relay 241 falls back, closingthe circuit of lamp 233. The operator thereupon withdraws plug 211 from jack 212, which results in relay 213 becoming deenergized. Relay 213, in retracting its upper armature, dei nergizes relay 201, which opens the locking circuit of relay 228 and at its outer armature closes the release circuit for the finder as follows: ground, contact 292 of key K, conductors 291, 290, armature and back contact of calling supervisory relay 203, conductor 202, outer armature and back contact of relay 201, conductor 200, conductor 109, right armature and back contact of relay 103, primary off-normal contact POX. release magnet RM, free pole of battery. Magnet BM, in attracting its left armature, locks itself over thegofi-normal contact to ground. .Vhen the finder brush shaft 119 is completely restored, this 011- at its inner armature,

normal contact opens and unlocks the release magnet. The finder in releasing opens the circuit of cut-ofi' relay CO.

Goin back to that oint in the operation where 't e removal 0 the receiver starts a finder seeking the calling line, it will be remembered that the initiation of such call energized group relay 103, which, in attracting its right armature, extended the conductor 109 grounded at the normal contact of key K, to the escape magnet 106 to initiate the primary movement of the finder brush shaft. In parallel with magnet 106, a quick acting relay, 131 is energized when relay 103 operates, this circuit being as follows: free pole of battery, relay 131, spring 132, conductors 133, 117, arm 1 and its first contact, armatures and back contacts of magnets PM, SM, conductor 108, right armature and front contact of relay 103, conductors 109, 200, outer armature and back contact of relay 201, conductor 202, armature and back contact of relay 203, conductors 290, 291 to ground at the normal contact 292 of key K. Relay 131, by attracting its right armature, locks itself directly to grounded conductor 108, and by attracting its left armature, opens the connection between the grounded left-hand armature of relay 102 and the out-starter wire 134, leadin to the escape magnet 106 of the next fin er. If the finder shown in Fig. 1 had been busy, relay 203 would have been energized, and consequently'the circuit for relay 131 just traced would not have been completed, and this relay failing to energize, the grounded left-hand armature of relay 102 would be connected over the left armature of relay 103 to the out-starter wire 134, leading to the escape magnet 106 of the next finder, to set the finder shaft in motion seeking the calling line. Thus, the starter wire is normally extended to the next idle finder. Assuming the finder shown in Fig. 1 to be the next idle finder, the circuit may be continued as follows: in-starter wire 135, left armature and back contact of relay 102, relay 103, conductor 136, right armature and back contact of magnet RM, resistance 137, free pole of battery. Relay 103, in attracting its left armature, connects the in and out-starter wires 135, 134 together, and in attracting its right armature, energizes the escape magnet 106 of such-finder as described, which, upon energizing, releases the side switch into position 2 to initiate the primary movement of the finder brush shaft. From this point on the operations'are the same as those already traced.

The particular feature of the present C11- cuit arra gement claimed herein will now be 'descr'bed. When the light load hours approach, all the operators except one leave their connecting circuits. Each group of lines has "a number of connecting circuits terminating at the night position.

Now, if all the connecting circuits term1-. nating at the night operators position serving any particular line group are taken for use and another call is initiated in such group, the artificial busy condition of the other positions is automatically removed and one of the finders thereof finds the calling line and lights the corresponding lamp 240, whereupon the night operator takes care of such call.

In detail, this operation is as follows: When a call is initiated, and, relay 102 operates, the attraction of the outer left armature of such closes the followin circuit for the first relay a of a train 0 slow relays a, b, and c: ounded left armature of rela 102 and its ront contact, conductor 175, 1e armature and back contact of relay (7, conductor 176, slow relay (1. to free pole of battery. Relay a in attracting its armature energizes relay 6 over the following circuit: free pole'of battery, slow relay b, armature and spring of relay a, conductor 7 177, to groundedconductor2175. Relay 6,

in attractin its armature, closes the following circuit or the relay 0: free pole of battery, slow relay 0, armature and spring of relay 6, conductor 177 togrounded conductor 175. Relay 0, in attracting its armature, closes the following circuit for relay d: free pole of battery, rela d, armature and' spring of relay 0, con uctor 177 to grounded conductor 175. Relay d in attracting its left armature opens the circuit of relay a and locks itself to grounded conductor 175. Relays a, b, and c thereupon fall back in succession. When relay 0 retracts its armature, the following circuit is closed for the relay e: free pole of battery, relay e, conductor 178, right armature and front co tact of relay d, armature and back contact d f relay a, conductor 177 to grounded conductor 175. v p

Belay e in attracting its armatures a 'ain connects ground to the conductors 179. Ihe grounding of these conductors renders the connecting circuits of, the other positions non-busy. The circuit for operating the escape magnet 106 of a finder to pass its side switch into, position 2 to initiate the primary movement of the brush shaft is now traced as follows: free pole of battery, magnets PM and 106, arm 1 and its first contact, armatures and back contacts of magnets PM and SM, conductor 108, right armature and front contact of relay 103, conductors 109,- 200, outer armature and back contact of relay 201, conductor 202, armature and back contact of relay 203, conductor 290, conductor 179, to ground at the armature and front contact of relay c.

When the calling line is found and the cut-ofi' relay CO thereof operated to deenergize the line relay LR, group relays 102 and 103 become inert. The retraction of the outer left armature of relay 102 unlocks relay at which, in retracting its right armature, deenergizes relay e. Relay 6 in retr'acting its armature again removes ground from the conductors 179, thus rendering the positions to whichsuch conductors belong again artificiallybusy. While the string of the slow relays a, b and 0 are started in operation by the initiation of every call, the line initiating such call is generally reached by the finder and the cut-01f relay thereof operated before the last slow relay 0 retracts its armatureto operate and lock up relay 0!. It is only when a finder is not available that the relay d is locked up to operate relay 6.

What is claimed is:

1. In a telephone exchange system, the combination with telephone lines, connecting circuits, automatic non-numerical switches for extending calling lines to said connectin circuits, and means for rendering certain 0 said non-numerical switches artificially busy, of a timing device set in operation by the initiation of a call, means automatically actuated when the calling line is extended to disable said timing device, and means actuated by said timing device if not disabled within a predetermined interval for removing. the artificial busy condition of said nonv numerical switches. 1

2. In a telephone exchange system, the combination with telephone lines, connecting circuits, automatic non-numerical switches for extending calling lines to said connecting circuits, and means for rendering certain of said non-numerical switches artificially busy, of 'a timing device including a train of slow relays, means for energizing said relays successively upon the initiation of a call, means actuated by the operation of the'last slow relay for deenergizing said relays succes-.

sively, and means actuated by the deenergization of the last slow relay for removing the artificial busy condition of said nonnumerical switches.

3. In a telephone exchange system, the combination with telephone lines, connecting circuits terminating in automatic finder switches to which said lines are multipled, opera tors positions at which said connecti circuits terminate, means for causing one fi said finders automatically to connect with a calling line, and means for rendering all of the finders busy except those of the connectmg circuits terminating at a given position, of a timing device set in operation by the initiation of a call, means automatically actuated when the calling line is extended to disable said timing device, and means actuated by said timing device if not disabled within a predetermined interval for removing the artificial busy condition of said finders.

4. In a telephane exchange system, the combination with telephone lines divided into groups, a group of connecting circuits terminating in automatic finder switches to which said lines are multipled in oups,

operators positions among which said con-i necting circuits are distributed in such a mannor that some of the connecting circuits serving each group appear at each position, means for causing one of said finders to connect with a calling line upon the initiation of a call therein, and means for rendering all of the finders busy except those of the.

moving the artificial busy condition of said finders.

5. In a telephone exchange system, the combination with telephone lines, line and cut-off relays LR and CO therefor, connecting circuits, automatic non-numerical switches for extending calling'lines to said connecting circuits and for operating the relays CO thereof, and means for rendering certain of said non-numerical switches artificially busy, of.a timing device including a train of slow relays (a, b, 0) and a relay 120, said relay 120 beingxenergized uponthe initiation of a call and causing the successive energization of said slowrelays, a relay e for removing theartificial busy condition of said switches, a relay 0! operated by the last slow relay 0 to connect said relay 6 to the back contact of the last slow relay 0 and to open the circuit of the first slow relay a, a locking circuit for relay d closed upon its energization and controlled by the relay 120, whereby the retraction of the armature of the last slow relay 0 before apredetermined interval completes the circuit of the relay 6 which restores the non-busy condition of the connecting circuits, while the retraction of such armature after the operation of the cutofi' relay of the calling line is without effect on relay 6.

In witness whereof I hereunto subscribe my name this 7th day of December, A. D.

SAMUEL B. WILLIAMS, JR. 

